In optical fiber communications, connectors for joining fiber segments at their ends, or for connecting optical fiber cables to active or passive devices, are an essential component of virtually any optical fiber system. The connector or connectors, in joining fiber ends, for example, has, as its primary function, the maintenance of the ends in a butting relationship such that the core of one of the fibers is axially aligned with the core of the other fiber so as to maximize light transmissions from one fiber to the other. Another goal is to minimize back reflections. Alignment of these small diameter fibers is extremely difficult to achieve, which is understandable when it is recognized that the mode field diameter MFR of, for example, a singlemode fiber is approximately nine (9) microns (0.009 mm). The MFR is slightly larger than the core diameter. Good alignment (low insertion loss) of the fiber ends is a function of the transverse offset, angular alignment, the width of the gap (if any) between the fiber ends, and the surface condition of the fiber ends, all of which, in turn, are inherent in the particular connector design. The connector must also provide stability and junction protection and thus it must minimize thermal and mechanical movement effects.
In the present day state of the art, there are numerous, different, connector designs in use for achieving low insertion loss and stability. In most of these designs, a pair of ferrules (one in each connector), each containing an optical fiber end are butted together end to end and light travels across the junction.
It can be appreciated that the process of attaching a connector to the end of a fiber, a process that often is performed in the field, requires human intervention, with consequent expenditure of time, and of uncertain accuracy. On the other hand, in the manufacture of jumper cables, i.e., relatively short cable lengths with connectors at each end, for use in making interconnections on a patch panel, for example, the production thereof is substantially completely a manufacturing process, which lends itself to automation, thereby eliminating or reducing human intervention. Virtually the entire process of producing a connectorized end on a jumper cable can be, and, in the present state of the art, is performed by machine or robotic components. However, one phase of the operation has proved difficult to achieve by automation, and that is the cleaving of the fiber contained in the ferrule so as to be flat and flush with the end face of the ferrule. U.S. Pat. No. 4,710,605 of Presby, U.S. Pat. No. 4,932,989 of Presby, U.S. Pat. No. 5,256,851 of Presby, U.S. Pat. No. 5,421,928 of Knecht, and U.S. Pat. No. 6,413,450 of Mays, Jr., each shows an apparatus for cutting or forming fiber ends by means of a focused laser beam. In all such arrangements, the beam is formed to taper to a focal point, thereby producing a Gaussian shape power distribution with its maximum power being along the center of the beam axis, whereas the power gradually decreases away from the center. As a consequence, the cleaved fiber has a slightly angled end face, which is not perfectly flat and flush with the ferrule end face. It then becomes necessary to abrade and polish the fiber end face to make it flat and flush, with a consequent undesirable expenditure of time and possibly stressing of the fiber. Some prior art processes include apparatus for holding the fiber at an angle corresponding to the angle of the beam taper, thereby producing a flat face orthogonal with the fiber (and ferrule) axis. This solution, however, introduces additional apparatus, which is undesirable and requires precise angular orientation of the fiber. Further, in the tilted fiber and ferrule configuration, the laser beam is also focused on the ferrule surface, which may cause a undesirable damage on the ferrule.
In prior art manual and/or automated systems for producing jumper cables, there is a large number of steps involved, from the cutting to length and coiling of the optical fiber cable to the final assembly of the connector. The steps involved, which will be discussed more fully hereinafter, include cutting and removing a portion of the outer jacket and Kevlar strength member (if any), stripping the buffer and coating to bare the fiber, and cleaving the fiber. The fiber is installed and cemented in the ferrule, and the end thereof cleaved to be flat and flush with the ferrule end. Because, as pointed out hereinbefore, the prior art cleaving methods do not produce a desired fiber end, several grinding and polishing steps are necessary, each step having a polishing apparatus and each consuming time and requiring, in total, a considerable amount of polishing consumables, (diamond polishing papers, for example). Each of the numerous polishing steps introduces some variability in the process, hence the large number of steps to achieve the desired flatness and flush end of the cleaved fiber. In the production of connectors, the number of connectors produced per unit of time, dubbed the beat rate, is a function of the number of polishing steps, the greater the number, the greater the beat rate. Thus, the necessity of several polishing stages, each with its consumables. When the number of polishing steps is large, it can be appreciated that the process is lengthened and the number of polishing apparatuses increased. Subsequent to the polishing steps and after testing of the ferrule and fiber end face, the connector is finally assembled on the end of the cable. It can be appreciated that a reduction of the number of process steps in the manufacture of connectorized jumper cables, and other types of connectorized cables to achieve an acceptable beat rate, is highly desirable.